Infection Pathology During Respiratory Syncytial Virus and Rhinovirus Single Infection and Co-infection

Abstract

INTRODUCTION: Respiratory syncytial virus (RSV) and rhinovirus (RV) are the most common co-detected viral-viral co-infections in hospitalised infants, which has been linked to increased disease severity; however, this link is still poorly understood. The aim was to identify whether there is a difference in viral replication, inflammation (interleukin-8 production (IL-8)) and cell damage (lactate dehydrogenase (LDH) release) in a human type-2 alveolar basal epithelial cells (A549) infection model during RSV or RV single infection and RSV/RV co- infection at various time points. METHODS: A549 cells (n = 3) were infected singly with RSV or RV, or co-infected with RSV and RV. Cell supernatants and RNA samples were collected at 0, 24, 48, 72 and 96-hours post- infection. RT-PCR was carried out to assess viral infectivity and replication capability of RSV, RV and RSV/RV at all time points. IL-8 and LDH production were measured to assess inflammation and epithelial damage of A549 cells respectively post RSV, RV and RSV/RV infections at all time points. RESULTS: There was no significant difference between the replication of RSV or RV single infection and that of RSV/RV co-infection at all time points. No statistical difference was seen during RSV or RV single infection and RSV/RV co-infection in IL-8 release at all time points. Furthermore, LDH production did not differ significantly during RSV or RV single infection and RSV/RV co-infection. CONCLUSIONS: Our results suggest that there is no difference in disease severity during RSV or RV single infection and RSV/RV co-infection. Further studies are needed to investigate the link between viral-viral co-infection and disease severity.